There is considerable concern about the amount of artificial space debris in orbit around the Earth. Even very small debris objects can cause significant damage to other objects in space as relative velocities in orbit can reach many kilometers per second. Some of the space debris orbiting the Earth includes large objects, ranging from inactive satellites to expended rocket booster stages. The debris objects, such as those mentioned, can cause serious damage to a spacecraft on collision and be a plentiful source of further smaller debris fragments in the event of a collision with a space vehicle or other debris objects. The amount of space debris already in orbit is thought to pose a threat to the continued use of certain orbital bands.
It is desirable to find a suitable method of neutralising the problems which debris objects present. It has been suggested that disused low Earth orbit (LEO) satellites could be deorbited and allowed to burn-up in the Earth's atmosphere, and that disused geosynchronous orbit (GEO) satellites, occupying valuable orbital slots, could be moved into graveyard orbits either side of the GEO band.
The idea of using a space vehicle to capture a debris object, in order to then deorbit it, has been suggested. However, performing this task safely, efficiently and reliably is made difficult by the nature of the debris. The objects in question vary greatly in size, shape and construction and they may also spin at different angular velocities. Moreover, there are debris objects about which little may be known concerning their internal structure. Debris objects may contain internal components which one would not wish to damage, for example a fuel tank or a nuclear reactor.
The invention was made in this context.